Such measuring instruments are carried, e.g., as compact, mobile gas-measuring instruments with warning function by individual persons on the body or on the clothing. Persons who are exposed to a gaseous hazard carry corresponding instruments in order to be optically and/or acoustically warned when a certain, preset gas concentration is exceeded.
Depending on the clothing and the activity of the user, the measuring instrument must offer the possibility of being able to be fastened to various pieces of clothing simply and securely, but detachably.
A nonpositive fastening with spring clamps is usually performed, wherein the holding force depends on the spring force, the surface finish and the shape of the holder as well as the nature of the pieces of clothing. Depending on the design embodiment of the holder, a relatively strong operating force is needed to open the holder. The spring force of the spring and its reliability of operation may lessen due to aging.